API 510 Corrosion Assessment 2

Question 1

When evaluating corrosion under insulation (CUI), which temperature range poses the HIGHEST risk for carbon steel?

Accepted Answer

25°F to 250°F (-4°C to 121°C)

Answer

CUI on carbon steel is most active in the 25°F to 250°F range where moisture can accumulate and not fully evaporate.

Question 2

A vessel exhibits uniform metal loss of 0.012 inches over a 2-year inspection interval. What is the calculated corrosion rate?

Accepted Answer

0.006 in/yr

Answer

Corrosion rate = total loss divided by years = 0.012 divided by 2 = 0.006 in/yr.

Question 3

Which type of corrosion is characterized by selective attack along grain boundaries of a metal?

Accepted Answer

Intergranular corrosion

Answer

Intergranular corrosion attacks the grain boundaries preferentially, often due to sensitization in stainless steels.

Question 4

API 510 requires that remaining life calculations use which corrosion rate when both short-term and long-term rates are available?

Accepted Answer

The more conservative (higher) rate

Answer

API 510 specifies using the more conservative (higher) corrosion rate to ensure safe remaining life estimates.

Question 5

What phenomenon occurs when two dissimilar metals are in electrical contact in a corrosive electrolyte?

Accepted Answer

Galvanic corrosion

Answer

Galvanic corrosion occurs when dissimilar metals are in electrical contact and immersed in an electrolyte, causing the more active metal to corrode preferentially.

(API 510) API 510 Inspector Certification Practice Test

(API 510) API 510 Inspector Certification Practice Test

API 510 Corrosion Assessment 2